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Wacky tach and losing power

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Old Feb 17, 2017 | 03:22 PM
  #1  
Matts Jeep's Avatar
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From: California
Year: 1998
Model: Cherokee
Default Wacky tach and losing power

Problems started about a week ago. Continually getting worse with more and more symptoms. started out with my tach flopping all around the gauge for a few seconds and while it goes crazy I lose mechanical power(seems like the skinny pedal is not connected to anything). when this happens if I let off the skinny it will die but if I pedal it a few times it come back to life and the tach settles back to normal. Next, it came to the point where the tach would go bouncy and it would die while I'm driving but if I pedaled it while I was still rolling it would pop back to life and drive fine. now it is to the point where the tach goes floppy(and when I say floppy I mean jumping thought the whole gauge not just a couple hundred rpm), and it completely dies. it left my stranded on the side of the highway last night and would not start back up. and ideas are welcome. also I replaced cap rotor wires and plugs and that did not help. I looked for chewed wires thinking it could be a short, found a few and fixed them but that did not fix it either. and all my fuses are good. also no CEL.
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Old Feb 17, 2017 | 03:34 PM
  #2  
jordan96xj's Avatar
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From: Syracuse, NY
Year: 1996
Model: Cherokee (XJ)
Engine: 4.0L
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Could be a few things, but it has the hallmarks of a Crankshaft Position Sensor that is failing, and sending a bunch of bad signal to the computer before it dies.

Similar:
https://www.cherokeeforum.com/f2/new...ometer-104595/

CPS Multimeter Test:
https://www.cherokeeforum.com/f51/testing-cps-5563/

Could also be general electrical problems due to poor connections/corrosion. So take some time to clean up your ground connections and battery terminals.
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Old Feb 18, 2017 | 11:42 AM
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Matts Jeep's Avatar
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Year: 1998
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Thanks for the links. I thought that might be it but I was hoping for something simpler as always. I'll try to test it today but we got a few inches of snow last night so that's gonna be fun.
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Old Feb 18, 2017 | 11:59 AM
  #4  
Matts Jeep's Avatar
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Year: 1998
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Also, if it does end up being the CPS is there any recommendations on where to get one? rock auto has one for $35 and Oreilly has one for $90 Napa's prices are high also.
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Old Feb 18, 2017 | 12:15 PM
  #5  
fb97xj1's Avatar
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From: PA
Year: 1997
Model: Cherokee
Engine: 4.0L
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Stick with Mopar.
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Old Feb 18, 2017 | 12:26 PM
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freegdr's Avatar
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From: Broward County Fl.
Year: 1989 xj sport 2dr
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Engine: 12 hole bosch Injectors
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Check ground wires by oil dip stick tube and fire wall to cyl head drivers side. Also battery cable connections.
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